ISSN:1062-8592    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

Human articular cartilage is a remarkably resilient tissue that is exposed to approximately 10 million cycles of loading per year and in many instances provides normal function for as many as 8 decades. Articular cartilage provides the bearing surface that allows bony segments to glide and rotate against each other and cushions peak stresses associated with physical activity. Articular cartilage tissue is composed of approximately 70% water, 25% extracellular matrix proteins, and 5% cells. The concentration of macromolecules, primarily collagens and proteoglycans influences the mechanical properties of the tissue, as does the assembly and organization of these components into an ordered structure. The mechanical properties of cartilage are also influenced by the interaction of the porous extracellular matrix and the fluid occupying the pores. In normal healthy cartilage, a delicate balance exists between the synthesis and degradation of matrix components, so that homeostasis is maintained and continued mechanical performance of the tissue is ensured.

ISSN:1062-8592    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

Healing of chondral injuries depends on the depth and extent of the lesion. A lesion that only penetrates through part of the cartilage's thickness and not through subchondral bone does not have the capacity for self-healing, because of the antiadhesive properties of the cartilage proteoglycans and the absence of access to blood or bone marrow cells. A layer of mesenchymal or synovial cells may cover the edges of such a partial defect when the peripheral proteoglycans are removed, and the defect may eventually fill with fibrous tissue when a scaffold of fibrin clot is inserted and may fill even better if growth factors are added. However, the regenerated tissue does not resemble cartilage, and its mechanical quality has not been reported. Cartilage defects that penetrate subchondral bone, result in spontaneous repair with fibrous or hyaline-like cartilage tissue with inferior structural, chemical, and mechanical properties. Precultivated autologous and allogenic cells, alone or combined with carriers or other types of biological materials, even permanent prostheses, have been used in defects reaching to subchondral bone or penetrating the subchondral bone plate, to improve the quality of spontaneous repair. The repair tissue in these methods ranges from hyaline-like cartilage to fibrous tissue but does not provide normal cartilage morphology, mechanical properties, and durability. The main problems in this method are the wide range of outcomes, the insufficient bond to adjacent cartilage, and the premature degeneration of the repair tissue, which was commonly seen when a method was tested for longer than 6 months. Furthermore, no evidence exists that shows any of the chosen methods to be essentially better than another, and it is still unclear whether any of them is better than simple drilling to bone marrow.

ISSN:1062-8592    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

The most frequently used drugs in human nonarthritic cartilage disease today are nonsteroidal antiinflammatory drugs, hyaluronan, and steroids. The role of these drugs in the treatment of cartilage damage, such as osteoarthritis, is unclear. Their use seems to be based on tradition, rather than on results of scientific studies. Rational drug treatment is developed on the basis of the knowledge of the pathogenetic mechanisms behind the disease. Research is increasingly advancing our knowledge of the processes involved in progressive nonarthritic cartilage disease. Investigators are currently focusing substantial work on the development of drugs that inhibit or retard the processes that are involved in cartilage matrix degradation. Preliminary results indicate that synthetic inhibitors of enzymes involved in matrix degradation in cartilage disease may open new avenues for the treatment of joint diseases.

ISSN:1062-8592    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

The introduction of new surgical techniques in the treatment of cartilaginous injuries has created hope for progress in the treatment of these challenging injuries. However, the results from these interventions vary according to the degree of arthritic changes within the joint, the type of postoperative rehabilitation program, and the length of follow-up. In this article, the scientific background concerning classification and repair techniques for cartilage injuries is reviewed. Also outlined are the clinical results reported to date. Anatomic location, size, depth, consistency, gross appearance, and whether the lesion is in a weight-bearing or non-weight-bearing area should be taken into account when performing an arthro-scopic diagnosis of cartilage injury. Radiographic analysis and magnetic resonance imaging will often be helpful in ruling out commonly associated joint injuries. The use of such new therapies as mosaic arthroplasty and autologous chondrocyte implantation has not been proved superior to the bone marrow-based techniques of microfracture or débridement of the lesion. Postoperative rehabilitation, including weight-bearing status and prevention of muscle atrophy, are considered just as important in achieving successful results. The long-term outcomes of operative repair of cartilaginous injuries in the prevention of joint degeneration is currently unknown and will rely on further progress in basic science and clinical orthopedic research.

ISSN:1062-8592    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

Multiple patterns of chondral injury have been described, with progressive superficial fibrillation of the articular surface, ostophyte production, and thickening of the subchondral bone associated with osteoarthritis. Clinically relevant chondral changes do not always begin at the superficial layers and proceed to deeper layers of cartilage. Another pattern of chondral change, often seen in younger patients, is the delamination and fracture of the uncalcified cartilage; the uncalcified cartilage separates from the underlying calcified cartilage and subchondral bone. Although described in 1957, the incidence and the significance of such changes have been reported only recently. Recent descriptions record isolated chondral fractures and delamination. This article reviews the literature regarding articular lesions of the knee dominated by the separation, fracture, or delamination of the intact uncalcified cartilage from the calcified cartilage base. Treatment techniques involving debridement, and techniques of subchondral bone penetration without cartilage or bone grafting are also reviewed.

ISSN:1062-8592    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

Lesions of human articular cartilage most often are the result of pathologically unclear disease processes that eventually lead to primary or secondary osteoarthritis. The incidence of the latter may even increase because of traumatic cartilage/bone injuries during sport activities. Likewise, osteochondritis dissecans can lead to osseous and cartilaginous lesions. Adult articular cartilage has only a very limited repair capacity after acute and chronic insults, and thus, cartilage lesions do not heal naturally and often undergo progressive degeneration. Until today, the only proven and effective treatment for the resulting pain and disability of such patients is joint replacement with a prosthesis. Repair of articular cartilage defects is still an unsolved problem. Many methods, including use of synthetic resorbable or nonresorbable materials, have been tried to enhance the quality of the repair tissue, but so far, no method has achieved reliable repair of normal hyaline cartilage with normal biomechanical properties and bonding to the surrounding cartilage. After publication of the first results of chondrocyte transplantation in patients with localized cartilage lesions of the knee joints by Brittberg et al. in 1994, the interest in this technique has grown steadily, and it should be further evaluated. The following review should enable the reader to understand better the unique nature of cartilaginous lesions, to recognize the difficulties and controversies involved in old and novel experimental methods of cartilage repair, and to evaluate critically the developments of orthopedic therapies in repairing articular cartilage lesions.

ISSN:1062-8592    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

Full thickness defects or injuries of the articular cartilage are often associated with disabling pain and impaired daily activities. These injuries may progress to secondary osteoarthrosis. It is important to treat these patients and try to accomplish regeneration of articular cartilage, especially in younger patients. Cells in the cambium layer of the periosteum are pluripotent and can differentiate into hyaline (or hyaline-like) cartilage. Autologous periosteum transplants, and autologous chon-drocytes—periosteum, have been used in the treatment of full thickness cartilage defects in the knee joint. The results vary. Postoperatively, the type of rehabilitation may be of great importance, e.g. continuous passive motion (CPM) in the immediate postoperative period.

ISSN:1062-8592    

出版商:OVID    

年代:1998

数据来源: OVID